Prenatal Diagnosis of Citrin Deficiency in a Chinese Family with a Fatal Proband

Citrin deficiency (CD) is an autosomal recessive disorder with SLC25A13 as causative gene that encodes citrin, the liver-type aspartate/glutamate carrier isoform 2 (AGC2). Neonatal intrahepatic: cholestasis caused by citrin deficiency (NICCD), the major CD phenotype at pediatric age, has been previously reported as a self-limiting condition with clinical presentations resolving between 6 months and 1 year of life. We report the prenatal diagnosis of CD in a family with a fatal NICCD proband. The proband was a 10-month-old male presenting cough for 8 days and jaundiced skin 1 day. Physical examination revealed fever, dark jaundiced sclera and skin, hoarse breathing sounds, and hepatosplenomegaly. Laboratory tests uncovered elevated cholestatic indices, increased ammonia, and prolonged activated partial thromboplastin time and prothrombin time, and reduced fibrinogen. Sonography showed the features of liver cirrhosis. Metabolome analysis uncovered large quantity of 4-hydroxyphenyllactate and dicarboxylates in urine and increased citrulline and methionine in blood. The patient passed away due to liver failure at his age of 13.5 months. Mutation analysis revealed him a homozygote of 851del4, a four-base deletion in exon 9 of SLC25A13 gene. On request of the parents who had a second fetus, prenatal diagnosis of CD was performed by PCR-electrophoresis following amniocentesis and amniocyte culture, and demonstrated the fetus a carrier of the same mutation. The fatal proband in the present report has provided clinical evidence challenging the traditional concept on NICCD prognosis. Moreover, as the first trial on CD prenatal diagnosis, this study might open a novel area for clinical management of CD.